The present invention relates to novel processes for producing 2-alkylidene-3-alkynals and 2-alkylidene-3-alkenals and to the novel alkynals, alkenals and acetals thereof so obtained.
U.S. Pat. No. 3,463,818 shows unsaturated aldehydes having various floral odors and processes for preparing such compounds. Japanese published application 72/43526 shows the synthesis of terpene derivatives having orange-like odors, and hexadienal derivatives are shown. Wiemann et al, Memoires Presentes Soc. Chem., 1966, 1760, describe nuclear magnetic resonance studies of some conjugated dienals, and a number of these compounds, including 2-ethylidene-3-pentenal are shown. 2-Propenyl-2-pentenal is mentioned in Chem. Abstracts 35, 6238.
West German published application No. 1,951,883 is said in Chem. Abstracts 75, 5246 to show preparation of dienals useful as perfumes. Tiffeneau et al, Comptes Rend. 204, 590 show the preparation of 2-alkylidene-3-alkenals.
U.S. Pat. Nos. 3,272,873; 3,453,317; and 3,493,619 show processes for preparing unsaturated aldehydes or for treating such aldehydes. U.S. Pat. No. 3,520,936 shows production of an unsaturated aldehyde, and U.S. Pat. No. 3,542,878 shows an aldol condensation using a tin catalyst.
Odiger et al Annalen 682, 58 (1955); Corey et al, J. Am. Chem. Soc. 90, 6816; and Wittig et al, Chem. Ber. 94, 676 show "alkylidenation" reactions utilizing phosphorous compounds.